ABSTRACT
<p><b>Objective</b>To determine the stability of androgen indexes by analyzing the relationship of androgen indexes with the results of late-onset hypogonadism (LOH) questionnaire investigations, and offer some reference for the application of the diagnostic criteria for LOH released by The Chinese Society of Andrology in 2009.</p><p><b>METHODS</b>This study included 1 003 males aged 40 years or older who had accomplished the questionnaires of Androgen Deficiency in Aging Males (ADAM), Aging Males' Symptoms Scale (AMS), and International Index of Erectile Function-5 (IIEF-5). We evaluated the correlation of androgen indexes with the results of the questionnaire investigation, repeated the examination of androgen indexes for the subjects with total testosterone (TT) ≤11.5 nmol/L after an average of 1.5 years, and analyzed the factors inducing changes of androgen indexes.</p><p><b>RESULTS</b>Free testosterone index (FTI) ≤ 0.42 (OR, 1.369) and calculated free testosterone (cFT) ≤ 0.3 nmol/L (OR, 1.302) were considered as the risk factors of LOH in AMS, and so were testosterone secretion index (TSI) ≤ 2.8 nmol/IU (OR, 1.679) and cFT ≤ 0.3 nmol/L (OR, 1.371) in IIEF-5. Paired t-test on the results of the examination performed twice showed significant differences in the levels of TT, TSI, cFT, and FT (P<0.05).</p><p><b>CONCLUSIONS</b>Decreased testosterone may cause the diversity of LOH symptoms and hence the fluctuation of androgens. Therefore, the diagnosis of LOH depends on androgen indexes, varied symptoms in the questionnaires, and relief of the symptoms after testosterone therapy.</p>